Fabric panel buildings are used to rapidly deploy a building and are often used for applications where a building is required quickly or for temporary purposes. Some uses include aviation buildings, storage and warehousing, agricultural buildings, military buildings, and buildings for sports and recreation. Fabric panel buildings have a framework consisting of I-beams, open webbed trusses, or other structural members that are secured to ground supports. The fabric panels are secured between the structural members and tension is applied to the fabric panels to remove wrinkles.
There are a number of approaches that have been used to add or remove tension to the fabric panels, but many of these approaches are not suitable for a number of reasons. Many of these approaches require adjustment from outside the structure which can be difficult, dangerous, expensive, and labor intensive. Other approaches place unnecessary wear and fatigue on the structure or fabric panels.
For example, U.S. Pat. No. 5,333,425 to Nickerson et al. discloses a nut that can be tightened to draw oppositely disposed guides toward the structural beam to add tension to the fabric membrane. This approach is extremely labor intensive as it can only be adjusted from outside the structure using hand tools and requires the removal of a weatherproofing cover to ensure the structure is waterproof. This approaches also requires an expensive custom I-beam structure to which a custom keder rail structure must be mated.
U.S. Patent Application No. 2014/0209258 to Wenstrand discloses a fabric tensioning system that can be adjusted from inside the building structure. A nut can be hand tightened to adjust fabric tension, but not enough clearance is provided to allow the use of power tools. An additional weatherproof flap is included but the tension on the weatherproof flap must be adjusted from outside the structure which negates the advantage of having a fabric panel tensioning mechanism adjustable from inside the structure.
U.S. Pat. No. 9,334,653 to Fox discloses a keder rail structure that includes a pair of protrusions that attaches to fabric panels on either side of the structural member. A tensioning tool is used to pull the keder rail into position and the keder rail is then secured in place to the building structure with a bolt that runs through the keder rail and additional clips that attach to the I-beams. This approach of using a tensioning tool is slow and labor intensive. Because a single keder rail structure attaches to both adjacent fabric panels, it is not possible to independently adjust tension on a single fabric panel, which also makes future replacement of a single fabric panel very difficult.
Many other approaches to installing fabric panels to the building structure require placing tension on the structural member of the building. For example, U.S. Pat. No. 4,137,687 to Sprung, U.S. Pat. No. 4,593,710 to Stafford et al., and U.S. Pat. No. 7,849,639 to Sprung all disclose methods of placing tension on the structural members of the building to adjust tension of the fabric panels. These approaches that place stress on the structural elements of the building are not ideal as they potentially damage the structure with unnecessary stress, offer limited tension adjustability once installed, and make replacing a fabric panel difficult and labor intensive. These approaches are also more expensive because they require additional parts and/or custom extrusions of the I-beams to include the spreader or tensioning elements.